The invention relates to a tread sole for athletic shoes consisting of rubber or another material having rubber-elastic properties. More particularly to soles having nubs uniformly distributed over the tread and oriented obliquely to the surface of the sole.
Tread soles of this type have been known, for example, from DOS (German Unexamined Laid-Open Application) No. 2,828,561. Sport shoes having such tread soles have also proven themselves best under the difficult, changing terrain conditions as in marathon or cross-country footraces.
The invention is based on the object of even further broadening the usage area for athletic footwear having tread soles of the aforedescribed type. In particular, athletic shoes with the tread sole according to this invention are to be suited for sports conducted on artificial grass or snow- and ice-covered hard courts.
This object has been attained according to the invention by a combination of features including obliquely oriented nubs being arranged exclusively as an outer row or rows in zones of the ball of the foot ankle joint and heel; shorter perpendicular nubs in a marginal tip zone; and expansion grooves a frontal region.
The obliquely oriented nubs provided along the rim of the sole in the areas of the ball of the foot, the ankle joint, and the heel ensure secure anchorage against lateral slipping. This nonslip property is still further enhanced by the feature that the tread sole exhibits increased flexibility transversely across the surface of the tread sole, due to the expansion groove or expansion grooves, so that the nubs arranged in the marginal zone of the sole can be fully effective even in case of a nonplanar ground surface or when the foot strikes the ground obliquely. In particular, it is ensured that the obliquely oriented nubs in the marginal sole zone of the tread sole, on account of the greater profile height, will grip the ground first and immediately, but due to the high deformability of these nubs, also the adjacent, uninclined nubs in the marginal zone of the tread sole will come very quickly and effectively in gripping contact with the ground. As a consequence, sufficient ground contact and thus adequate nonskid behavior are ensured even in case of extreme ground conditions and difficult phases of the athletic activity.
These and other objects, features and advantages of the present invention will become more apparent from the following description when taken in connection with the accompanying drawings.